[PATCH] tcp: Pass union tcp_conn pointer to destroy and splice timer functions - dev

19 Nov 2022

The pointers are actually the same, but we later pass the container
union to tcp_table_compact(), which might zero the size of the whole
union, and this confuses Coverity Scan.

Given that we have pointers to the container union to start with,
just pass those instead, all the way down to tcp_table_compact().

Signed-off-by: Stefano Brivio &lt;sbrivio(a)redhat.com&gt;
---
 tcp.c        | 17 +++++++++--------
 tcp_conn.h   |  4 ++--
 tcp_splice.c | 16 ++++++++++------
 3 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/tcp.c b/tcp.c
index 8874789..ff12dfa 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1376,16 +1376,18 @@ void tcp_table_compact(struct ctx *c, union tcp_conn *hole)
 /**
  * tcp_conn_destroy() - Close sockets, trigger hash table removal and compaction
  * @c:		Execution context
- * @conn:	Connection pointer
+ * @conn_union:	Connection pointer (container union)
  */
-static void tcp_conn_destroy(struct ctx *c, struct tcp_tap_conn *conn)
+static void tcp_conn_destroy(struct ctx *c, union tcp_conn *conn_union)
 {
+	struct tcp_tap_conn *conn = &conn_union->tap;
+
 	close(conn->sock);
 	if (conn->timer != -1)
 		close(conn->timer);
 
 	tcp_hash_remove(c, conn);
-	tcp_table_compact(c, (union tcp_conn *)conn);
+	tcp_table_compact(c, conn_union);
 }
 
 static void tcp_rst_do(struct ctx *c, struct tcp_tap_conn *conn);
@@ -1535,13 +1537,12 @@ void tcp_defer_handler(struct ctx *c)
 	for (conn = tc + c->tcp.conn_count - 1; conn >= tc; conn--) {
 		if (conn->c.spliced) {
 			if (conn->splice.flags & CLOSING)
-				tcp_splice_destroy(c, &conn->splice);
+				tcp_splice_destroy(c, conn);
 		} else {
 			if (conn->tap.events == CLOSED)
-				tcp_conn_destroy(c, &conn->tap);
+				tcp_conn_destroy(c, conn);
 		}
 	}
-
 }
 
 /**
@@ -3395,10 +3396,10 @@ void tcp_timer(struct ctx *c, const struct timespec *ts)
 
 	for (conn = tc + c->tcp.conn_count - 1; conn >= tc; conn--) {
 		if (conn->c.spliced) {
-			tcp_splice_timer(c, &conn->splice);
+			tcp_splice_timer(c, conn);
 		} else {
 			if (conn->tap.events == CLOSED)
-				tcp_conn_destroy(c, &conn->tap);
+				tcp_conn_destroy(c, conn);
 		}
 	}
 
diff --git a/tcp_conn.h b/tcp_conn.h
index 4a8be29..a146276 100644
--- a/tcp_conn.h
+++ b/tcp_conn.h
@@ -181,8 +181,8 @@ extern union tcp_conn tc[];
 
 void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn *new);
 void tcp_table_compact(struct ctx *c, union tcp_conn *hole);
-void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn);
-void tcp_splice_timer(struct ctx *c, struct tcp_splice_conn *conn);
+void tcp_splice_destroy(struct ctx *c, union tcp_conn *conn_union);
+void tcp_splice_timer(struct ctx *c, union tcp_conn *conn_union);
 void tcp_splice_pipe_refill(const struct ctx *c);
 
 
diff --git a/tcp_splice.c b/tcp_splice.c
index e2f0ce1..72b1672 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -251,10 +251,12 @@ void tcp_splice_conn_update(struct ctx *c, struct tcp_splice_conn
*new)
 /**
  * tcp_splice_destroy() - Close spliced connection and pipes, clear
  * @c:		Execution context
- * @conn:	Connection pointer
+ * @conn_union:	Spliced connection (container union)
  */
-void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
+void tcp_splice_destroy(struct ctx *c, union tcp_conn *conn_union)
 {
+	struct tcp_splice_conn *conn = &conn_union->splice;
+
 	if (conn->events & SPLICE_ESTABLISHED) {
 		/* Flushing might need to block: don't recycle them. */
 		if (conn->pipe_a_b[0] != -1) {
@@ -283,7 +285,7 @@ void tcp_splice_destroy(struct ctx *c, struct tcp_splice_conn *conn)
 	debug("TCP (spliced): index %li, CLOSED", CONN_IDX(conn));
 
 	c->tcp.splice_conn_count--;
-	tcp_table_compact(c, (union tcp_conn *)conn);
+	tcp_table_compact(c, conn_union);
 }
 
 /**
@@ -824,12 +826,14 @@ void tcp_splice_init(struct ctx *c)
 /**
  * tcp_splice_timer() - Timer for spliced connections
  * @c:		Execution context
- * @conn:	Spliced connection
+ * @conn_union:	Spliced connection (container union)
  */
-void tcp_splice_timer(struct ctx *c, struct tcp_splice_conn *conn)
+void tcp_splice_timer(struct ctx *c, union tcp_conn *conn_union)
 {
+	struct tcp_splice_conn *conn = &conn_union->splice;
+
 	if (conn->flags & CLOSING) {
-		tcp_splice_destroy(c, conn);
+		tcp_splice_destroy(c, conn_union);
 		return;
 	}
 
-- 
2.35.1


    